# Solving Non-linear Systems of Equations

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## Objective

SWBAT solve systems of equations involving a linear function and a quadratic function both algebraically and graphically. SWBAT understand the process of factoring polynomials as a tool to solve non-linear systems

#### Big Idea

Students create and interpret non-linear systems of equations and use technology to find and understand the solution(s)!

## Entry Ticket: Comparing Stocks (Linear and Exponential Growth)

20 minutes

In this Entry Ticket I give students practice solving a system of equations with graphing. I also present them with a new situation: What happens if one of our functions in a system is not linear? I strongly favor this HSA-REI Common Core standard because it sets a high bar of expectations for learners to make connections, comparisons, and explanations.

Today's Entry Ticket takes a bit longer than the typical 10-15 minutes. 20 minutes is usually enough time for students to engage fully with the activity. The task encourages students to work on a relevant problem with enough scaffolding to practice higher-level thinking skills in a collaborative environment. The added bonus to this word problem is it gives a preview of  a coming attraction, Comparing Linear and Exponential Functions, a topic we will cover later in the year!

## Active Note-Taking: Solving Non-Linear Systems

20 minutes

To continue the discussion around non-linear systems I show one or two Khan Academy video examples dealing with the topic. During this time students are actively taking Two-Column notes and I am pausing the video and making annotations to the video to check in on student understanding. Each video presents examples of a linear function intersecting with a quadratic function.

Video 1

For most of my classes, I like to show a second example video. The reason for showing two videos addressing the same topic is that many of my students need to see a particular type of problem more than once in order to understand the big idea. For my advanced and honors sections, I typically only show the first video.

Video 2

## Collaborative Work: Solving Systems of Non-Linear Equations

30 minutes

After the video note-taking and discussion, I allow students to use an iPad from the  classroom set that I have available to practice solving examples of non-linear systems. Today, I plan for students to work on the section of the Khan Academy website focusing on Solving Non Linear Systems. I encourage my students to complete the practice problems on the site while working in small groups.

My students find these problems challenging at this point in the course. As a result, I am actively supporting students throughout this activity. I also encourage students to seek help from their group members. Some students like to refer back to their notes or to the example videos.

In order to enable the sharing of reasoning, I ask each group take a screen shot of at least one solution and annotate it for a presentation.

Instructor's Note: There is an option on Khan Academy for a sketchpad where students can take notes on the screen.

At an appropriately timed moment, I plan to project a group's work and ask the group to give a short presentation to the class about the solution that they chose to capture. I generally ask several groups to present in sequence, but it is possible to break them up a little more.

## Exit Ticket: Take Off! Solving Systems of Non-Linear Equations

10 minutes

For the Exit Ticket I have students complete a problem-based activity comparing the flight trajectory of two planes (a picture of the graphical solution is a resource in this section:Graphical Solution for Exit Ticket: Solving Non-Linear Systems).

The intent of this problem is to have students think about different applications of the concepts and skills they have used to solve systems with non-linear functions.

Students can also complete the Exit Ticket for homework and/or elaborate more on their thinking by completing a written response to their work to the problem as a homework assignment.